I have a Kindle, but have had a lot of problems with the screen shorting out. Other than that I love love love it. I would wait for the Kindle Fire to come out. It looks amazing.
My DD has had a nook for a couple of years now and loves it. I got one for my birthday and love it, even though I still go to my paper books for re-reading! My mom has a kindle and loves it; I don't think you can go wrong with either of them.
I love my I Pad. I read a lot on it but get so much more done, like reading about you ladies too. I also pay bills, shop, learn. It is of course more pricey but after saving for months and months got it and love it. I also have some great learning programs for my preschooler on it.